Lubricating compositions



we provide United States Patent Crystal Lakey-lll -assignors ito'The'Pure Oil Company,

Chicago, 111., a corporation of Ohio No Drawing. "Filed May 14,1957,"Ser.No. 658,940

Claimsr 01; 252-464 Thisfinvention "relates'to lubricating oiloompositions containing smallamounts of sulfurized isoprenoidcompounds'and'small amountsof organiccompounds containing phosphorus, .arseniciorantimony, which compositions lexliibitimproved antiwear properties andoxidation stability, Morekparticularly, theinvention relates to the uimvery that theflmcombination of sulfurized isoprenoid compoundsandorgariophosphorus, organoarsenic or orjganoantimonycompounds inlubricating oilsforms a superior 'antiwear composition as, exemplifiedby itsperforr'nancerin "the four ball extreme pressure machine, whereinasynergistic effect hasbeen found .to take place between the. compoundsof the aforestatedgeneral classification. a l

Organocomp'ounds of groupVB elements, that is, phosphorus, arsenic,antimony and-bismuth, are bestknown for their inhibition of oxidationprocesses,although certain of these compounds are described as havingsome extreme pressure properties when used in lubricating oilcompositions. Similarly, sulfurized isoprenoid compounds are known fortheir ability to impart oxidation stability and non-corrosive propertiestolubrica'ting compositions used in the presencevof alloyed bearings.Sulfurized isoprenoid compounds have in some instances been used fortheiriextreme pressure properties. However, it is.also well-known thatcomplex addends of the types aforementioned, which are efiective forimprovement-indetergency,

oxidation resistance or corrosion resistanceof lubricating oils, areoften prone to produce high wear-rates'when-used in; the lubricationof=-stee1 lsliding on steel. Known detergents, oxidation inhibitors, andcorrosion-preventing adtlends are generally considered to-be ineffectiveas extreme pressure agents under the severe conditions that are found"jiri; modern extreme pressure tests, such as the Shell fouroball test:g

The present invention is predicated on the-unexpected discoverythat-thecombination of antioxidants and detergpnts consisting of s ulfurcontaining isqprenoid com- 4 ndsand,organooonipounds of phosphorus,arsenic and ,[aruin onyexerts a synergistic antiwear efiectandproduceslovr wear rlateseas measured by the four ball test. The estraordinaryefi ect of' the specific combination of aduenqs t-ur ,of theadd 'dsnamely the organocompouiids of group YB, elements, rpducesiiar greater'wear ,with the 'mineral ,lubricat' g oilrthap the oil alone prod ucesi,Furthermore,

{it will; be demonstrated that the unusual antiwear prop- H 11 1entionfis emphasized by the, factithat one i aerties ofthecombination,of addends o f this invention is rtain members of thebroad group of ch they fall, such as combinations of uthines',representing the remaining meman extreme pressure lubricatingcomposition icontaining the combination oi: sulfurized isoprenoid com:

compounds, withjsulfurized, isoprenoids, ,prihi arylobject ofthisinvention is to mer ts of f f p' VB tha'di'ene and terpinolene. i

revised edition, 1953) excluding bismuth and nitrogen.

The isoprenoid compoundswhich are employed to produce the sulfurizedderivatives used as a part of the composition of this invention include1 the alicyclic, monocyclic,and dicyclic terpenerhydrocarbons, and arewellknownin the art. The terpenes have the general formula C H and manyarediolefinic derivatives-of cyclohexane. The more complex alicyclicterpenes are the sesquiterpenes, C H and the.polyterpenes (C H Among theopen-chain terpenederivativesare 2,6-dimethyloctatriene, geraniol,linalool, citronellol, citrolellal and rhodinal. Among themono'cyclicterpe'nes which are considered to be derivatives of p-menthane,orHl-methyl-Lisopropylcyclohexane, are a-terpinene, gamma-terpinene;u-phellandrene, fi-phellandrene, terpinolene, limonene andmenthadiene,B-ter'pinene and pseudoli-monene. The most im- 'portant monocyclicterpenes are limonene, a-terpinene and a-phellandrene. Para-menthane maybe derived from 'menthol by reduction, menthol being associated withterpenes in essential oils. \Otheroxidation derivatives of -p-menthai1e,also associated with terpenes in essential oils,

are carvomenthol, pulegone, u-terpineol, menthane and carvone.

d-Limonene'is found'in all citrusoils. l-limonene occurs in pine needlesand fir cones and oil of peppermint. The racemic modification,dipentene, is found in many essential oils. 1 Dipentene is found inturpentines and obtained by thedistillation of pine wood. *Dipentene maybe regarded a dimer ofisoprene and may be produced therefrom bypolymerization, ot-Teipineol can be formed from the dehydration ofterpin hydrate which maybe produced from dipentene or geraniol.

Among the dicyclic terpenes which are considered to be cyclohexane withabridge of one or more carbon atoms, the" most important membersarejcarene, pinene, and camphane. Thesedicyclic isoprenoidsmay beconsideredto be derivatives of p-menthane byhaving-theisopropyl' groupclose abridging ring acrossthe cyclohexane ring. tandfl-Pinene areobtained, the former in a proportion of 9=Q%,by distillation of theyellow pine resinexudate from pine' trees. Turpentine oils containp-cymene. Terpinolene,a monocyclic diene, is prepared synthetically fromterpineol by dehydration with oxalic acid.

H Fenchone is another bicyclic' te rpenede rivative under the camphanegroup and is isomericwith camphor. The treatment of a-pinenewith dryhydrogen iodide produces bornyl iodide which on reduction yieldscamphane.

The isoprenoid compounds found in naval stores 1 products may bevused,such as the constituents of a-pinne, gum andtwood turpentines, and itheconstituents ofdipenteneml22 or pine oils. range'fromcyelofenchenelboiling at about 143 i'C. .to u- Specifically, thesematerials terpineol boilingtat 237 C., includingsuchwell-knownisoprenoids as a-pinene, camphane," fl-pine-ne, ot-terpinene,

dipentene, 'p-cymene, 'gamma terpinene, 2,4( 8 para-men- Typicalcommercial proprietary terpene products by prenoid compounds scribed inthe following United States Patents may be used:

1,844,400Kobbe 2,417,305-Know1es 2,443,823-Ho1t V 2,689,846- Beegle Ingeneral, the 'sulfurization of the isoprenoid is carried out by addingan amount of sulfur which is-stoichiometrically in excess of the amountrequired to react with the doublebonds present in the isoprenoid, andheating the mixture in a kettle or stainless steel autoclave attemperatures ranging from 250" F. to 400 F. for a time sufiicient tocomplete the reaction. The isoprenoid compound used should have at leastone unsaturation in the molecule. In general, it is preferred to useordinary flowers of sulfur during the sulfurization step in proportionsof about 20 to 35 parts by weight, especially 25 to -30 parts of sulfur,for each 100 parts of reaction mixture, or about 25 to 54%, based on theweight of isoprenoid compound. The ingredients may be combined byheating the isoprenoid compound and adding the sulfur thereto; or,'thesulfur may first be melted and the terpene added gradually thereto; or,the ingredients may be combined .without prior heating and thereafterheated together to a temperature above the melting point of the sulfur.This is followed by further heating to about 300, to 400 F. Non-limitingexamples follow:

EXAMPLE I Three hundred grams of terpinolene and 90 grams of sulfur aremixed and placed in a 1000 cc. stainless steel autoclave. Heat isapplied and the mixture is maintained at about 340 F. for about 30minutes. The temperature is raised to about 360 F. for another 30minutes with agitation. A pressure of about 50 p.s.i.g. develops. Theautoclave is then cooled and the reaction mixture is subjected to vacuumsteam-stripping to 300 F.

at. about 15 mm. Hg.. The product may be used as such, or purified bydilution with an equal volume of benzene and refluxed with agitation forfour hours at 185-190 F. in the presence of a solution consisting ofabout 600 grams of water, 300 grams of sodium sulfide (Na S-9H O), and100 grams of sodium hydroxide.

Themixture is thenqallowed to cool, 500 cc. of pentane are addedsan'dthe mixture is shaken. A bottom layer of a dark orange-red liquid isdrawn off and the upper layer .is washed several times. with water. Thistop layer is filtered and the benzene and pentane is removed byevaporation on a steam bath.- The product, sulfurized terpinolene, is ayellow-brown liquid containing about 29 to 30% sulfur.

' EXAMPLE II Two hundred grams of steam-distilled pine oil, containingas its main constituent alpha-terpineol (B.P. 422-424 F.), is heated at220 F. with 50 grams of sulfur. Asthe temperature rises, the sulfurmelts and dissolves in the pine oil. When the temperature reaches;

a about 350 F., ebullition takes place and an exothermic .reactionbegins which brings the temperature to about 375 F. After; heating for4-5 hours at 375400 F., a homogeneous mass is obtained and purificationis carried out asin Example I. I i

' .EXAMPLE III By heating600'grams of terpinolene to 330 F. in a l Ckflask equipped'with a mercury-seal stirrer'and two refluxcondensersjadding gradually 180 grams of "sulfu'lrthrough'one ofthecondensers at a rate to mainf 'tainthe temperaturea't 350 F.,.heatingto about 350'F.

for. 2 /2 hours; cooling, filtering, -and vacuum steam- 'stripping to300 F; and purifying in accordancewith EXample 'I,-.aprbductQcontainingabout 29% sulfur, a

- -;yellowish-brown i oil, is obtained.

he qrsa cs pqun s'atmosphe es. se c a timony tobe used in accordancewith this invention may.

have organic radicals of the aliphatic, carbocyclic, including alicyclicand aromatic, and heterocyclic series having a total of from 3 to 30carbon atoms. Thus, the phosphines, arsines and stibines includecompounds which 5 contain the specific groups of trimethyl,dimethylethyl,

methylethylpropyl, methylethylcetyl, dibutylcetyl, triethyl, tripropyl,triisopropyl, tributyl, triamyl, dimethylbutyl, tricety l,methyldiphenyl, diethylbenzyl triphenyl, tritolyl, and tripyridyl. Otherspecific compounds include 'dibutylphenylphosphine,dilaurylphenylphosphine, and diwaxphenylphosphine. Particularlyapplicable to the invention are those organocomponnds of phosphorus,arsenic, and-anti-mony in which the organo portion of the moleculecontains only carbon and hydrogen.

In order to illustrate the invention, a number of lubricatingcompositions were prepared and subjected to tests on the shell four-ballEP machine in which a steel ball is rotated in contact with 3 stationaryballs submerged in the test oil. This machine may be used'to determinecharacteristic properties such as wear-rate under various conditions,load-carrying capacity, or ability to prevent seizure and welding underhigh loads. The test used to evaluate the oils of this invention was awear test of 5 minutes duration, a rotational speed of 1800 r.p.m., for

the top ball, and an applied load of 20 kg. Wear measurements are theaverage diameter in mm. of the scars produced by the rotating ball onthe three stationary balls. A low-wear lubricant will produce a scardiameter only slightly greater than the diameter ofelasiic indentationof the balls, which in the caseof the stated load and ball compositionused is 0.24 Table I shows some results obtained with the compositionsof our'invention containing triphenyl derivatives of group VB elements.

Table I Lubricant Composition, Wt. Percent 4-Ba1l l VtVear Group VOrgano- Increase compound Sulfur- Basic 170 vis. in av. scar izedBa-Sul- Mineral dia. over terpene fonate Oil Hertz Element Wt. Perdia.,mm.

cent

1. l 0.7 98. 2 0.03 1.1 0. 7 5. 3 92. 9 0.03 1.1 98. 9 0. 34 1.0 0.7 6.393.0 0. 03 1. 0 a 90. 0 0. 04 0.8 V 0.7 5. 3 98. 5 0.02 0.8 i 99. 2 0.050.7 5. 3 94. 0 0.12 0. 7 99. 3 0. 08 100.0 0.14 0.8 0. 7 5.3 93.2 0.090.8 99. 2 r 0513 1.4 -0.7 5.3 92.6 0.20

It will be seen from Table I that antiw'ear properties are exhibited toa marked degree by oil blends containing the additive combinationjofsulfurized terpene and a phosphine arsine or stibine. The antiwearproperties are also maintained in are presence of a commonly used "motoroil detergent additive, basic barium'petroleum'sulfonate." fin thistable the average wear values were obtained from three or moreindividual runs for each lu- "bricantfiThe individual, additives do' notnecessarily show antiwear properties; ,in fact, triphenylstibine in:mine'ral oil shows a higher wear rate than mineral oil alone. Examplesof oil; blends containing brganocompounds of the other two elements jofgroupVB, vi'z.,

nitrogen'and bismuth, are included to compafethe in- TOQferiorwearprotection'afiorded by combinations ofyaddiltivescontaining thesetwoelements with the sulfurized .t p -f Components. of "the abovelubricantcompositions may i be further identifiedfas follows. Theorganoc ompounds of group VB elements withwhich' mamyemia rs'ooav cernedwere all triphenyl derivatives and equivalent molar concentrations wereused. The sulfurized terpene was a commercial product containing 29.4wt. percent sulfur and having a specific gravity of 1.164. The sulfonatewas a commercial basic barium petroleum sulfonate containing 15.9 wt.percent sulfated ash, and having a total base number of 30. The mineraloil in the above blends was a Mid-Continent solvent-refined neutral oilwith a viscosity of 170 SUS at 100 F.

Although the lubricating oil compositions of this invention areillustrated by compositions containing a major proportion of a neutraloil, a minor proportion of a compound selected from the group consistingof triphenylstibine, -arsine, and -phosphine, used at a concentration of0.8 to 1.1 wt. percent, and a minor proportion of a productcharacterized as a sulfurized terpene, used at a concentration of 0.7wt. percent, it is to be under stood that the invention encompassesalkyl, aryl, alkaryl, arylalkyl, carbocyclic, including alicyclic andaromatic and heterocyclic phosphines, stibines and arsines, in which theorganic radicals are the same or dilferent. It is apparent also thatother lubricating oil fractions may be used and that the proportions ofthe different constituents may vary within the broad limits disclosed.Other additives, such as detergents and pour depressants normally usedin modern motor oil formulations, can also be incorporated whilemaintaining the advantages of the preferred combination of sulfurizedterpene and triarylstibine, arsine or phosphine, or other antiwearadditive combinations as set forth herein.

What is claimed is:

1. A lubricating composition comprising a major portion of a minerallubricating oil, about 0.2 to 5.0 weight percent of a sulfurizedterpenic compound selected from the group consisting of sulfurized pineoil, sulfurized terpinolene, sulfurized dipentene and sulfurized pinene,and about 0.2 to 5.0 weight percent of an organocompound selected fromthe group of triphenylphosphine and triphenylstibine said sulfurizedterpenic compounds and said organo-compound being essentially the onlyantiwear constituents present in said composition.

2. A lubricating composition comprising a major portion of a minerallubricating oil and about 0.7 weight percent of a sulfurized terpeniccompound selected from the group consisting of sulfurized pine oil,sulfurized terpinolene, sulfurized dipentene and sulfurized pinene andabout 0.8 to 1.1 weight percent of an organocompound selected from thegroup consisting of triphenylphosphine and triphenylstibine saidsulfurized terpenic compound and said organo-cornpound being essentiallythe only antiwear constituents present in said composition.

3. The lubricating composition of claim 2 in which the sulfurizedterpenic compound is sulfurized pinene.

4. The lubricating composition of claim 2 in which the sulfurizedterpenic compound is sulfurized pine oil.

5. The lubricating composition of claim 2 in which the sulfurizedterpenic compound is sulfurized terpinolene.

6. The lubricating composition of claim 2 in which the sulfurizedterpenic compound is sulfurized dipentene.

7. The lubricating composition of claim 2 in which the organocompound istriphenylphosphine.

8. The lubricating composition of claim 2 in which the organocompound istrlphenylstibine.

9. An extreme pressure lubricant comprising a major portion of a minerallubricating oil, about 0.7 weight percent of sulfurized terpene andabout 1.1 weight percent of triphenylstibine said sulfurized terpene andsaid triphenylstibine being essentially the only antiwear constituentspresent in said lubricant.

1 0. An extreme pressure lubricant comprising a major portion of amineral lubricating oil, about 0.7 weight percent of sulfurized terpeneand about 0.8 weight percent of triphenylphosphine said sulfurizedterpene and said triphenylphosphine being essentially the. only antiwearconstituents present in said lubricant.

References Cited in the file of this patent UNITED STATES PATENTS2,149,271 Butz Mar. 7, 1939 2,334,566 Lincoln Nov. 16, 1943 2,443,823Holt June 22, 1948 2,643,248 Brennan June 23, 1953

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PORTION OF A MINERALLUBRICATING OIL, ABOUT 0.2 TO 5.0 WEIGHT PERCENT OF A SULFURIZEDTERPENIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFURIZED PINEOIL, SULFURIZED TERPINOLENE, SULFURIZED DIPENTENE AND SULFURIZED PINENE,AND ABOUT 0.2 TO 5.0 WEIGHT PERCENT OF AN ORGANOCOMPOUND SELECTED FROMTHE GROUP OF TRIPHENYLPHOSPHINE AND TRIPHENYLSTIBINE SAID SULFURIZEDTERPENIC COMPOUNDS AND SAID ORGANO-COMPOUND BEING ESSENTIALLY THE ONLYANTIWEAR CONSTITUENTS PRESENT IN SAID COMPOSITION.